1. Field of the Invention
The present invention relates to a network simulation technology, and more specifically to a network simulation model generation apparatus, method, and a storage medium storing the program for realizing the method.
2. Description of the Related Art
Recently, the scale of networks such as Internet has been quickly extended. In addition, the types of networks have been shifted from voice communications such as telephone, etc. to data communications and multimedia communications. Especially, it is predicted that the multimedia communications capable of transmitting a large volume of data at a high speed will lead this field in the future, and that there will be much heavier traffic in the networks. Furthermore, with network appliances of higher performance, the configuration of a network will be more complicated, and a frame relay network, an ATM (asynchronous transfer mode) network are connected to a router, which is an important network appliance forming part of Internet, thereby increasing the structure of a VPN (virtual private network), an IP over ATM, an IP over SONET, an IP over WTM, etc. in the future.
In the above described high-level network field, it is assumed that a simulator has a more and more important function in realizing the optimization of the structure of network resources and arrangements, evaluating the influence of heavier traffic on the networks, etc.
Such a network simulator predicts various information such as the traffic in a network, etc. based on a simulation model of a network. Conventionally, the above described simulation model has been generated and managed by the system described below.
a) System Manually Set by a User
In this system, a user manually generates a simulation model using the tool for generating a simulation model.
b) System Using a Database
In this system, marketed simulation models (simply referred to as models) of network appliances of vendors are put in a database. Then, the user selects a model of a network appliance from the database, and generates a simulation model of the network.
c) Network Management Tool Cooperative System
In this system, the configuration of a network, the traffic of a network, etc. are collected using the network management tool such as a marketed network diagnosis tool, etc. According to the collection information, a simulation model of the network can be generated.
However, there has been the following problem with the above described conventional system.
a) System Manually Set by a User
In this system, since the user has to check in detail the network whose simulation model is to be generated, and to collect the information required to generate the model, the user has a heavy operation load. Furthermore, to collect the above described information, it is necessary for a user to be familiar to the network search technology and the simulation technology. Therefore, a user who is generating a simulation model has to be well-trained in these technologies. As a result, only an expert having a good knowledge of the technologies can generate a simulation model.
b) System Using a Database
There is the problem with this system that a simulation model may not be generated when the database does not contain a model of a network appliance required for the simulation model to be generated. In addition, each time a new network appliance is brought to the market, it is necessary to add a model of the network appliance to the database, and update the database. Therefore, maintaining the database has a heavy operation load, and the management is costly.
c) Network Management Tool Cooperative System
Since collectable information is limited in this system, a simulation model may not be correctly generated with the present situation of the network well reflected. That is, since the information collected by the network management tool is the information about the usage state of the network such as a traffic flow, the information indispensable in generating a simulation model of a network such as the information (transmission speed, capacity, etc.) about the performance of a network appliance may not be obtained.
Furthermore, in any of the systems a), b), and c), there have been the following problems with the generation and the management of a simulation model.
1) Costly Computing Process for Excess Use of a Detailed Model, and Limit to an Applicable Network
Normally, in a simulation, the detail level of a model is adjusted depending on the influence on a result. Conventionally, an adjustment is manually made by the user, or a detailed model is used without adjustment. However, if a detailed model is used without adjustment, the most detailed model is applied to all models, the entire simulation cost soars high because the more detailed a model is, the higher the computation cost becomes.
In addition, the increased computation cost of the simulation reduces the scale of a network to be simulated when the entire cost is limited.
2) Difficult Simulation Between Networks Due to Management Problems
Generally, a large scale network is divided into a plurality of lower networks (subnetworks), and each lower network is managed by a different manager. A conventional simulator is individually operated by each manager of each of the lower networks. A simulation model of each lower network is also managed by the management system.
However, when a simulation model spanning plural lower networks is generated, it is necessary to collect the management information about another lower network. Nevertheless, it is very hard to successfully generate such a simulation model because there occur individual problems with the operation of each lower network (security, optional configuration amendments, etc.).